Moisture absorbing calcium chloride crystals
 

I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Are there like to be any nasty substances released into the air as it
dries?

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

Thanks,

Daniele

Moisture absorbing calcium chloride crystals
 

"D.M. Procida" wrote in
message
...
I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Are there like to be any nasty substances released into the air as it
dries?

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

If you leave it long enough you will get just liquid, the situation that you
describe is because the liquid is saturated.

I wouldn't bother trying to dry the stuff, you'll have an awful job
hammering the resultant solid block of the stuff back up, and it's pretty
cheap!

Julian.

Moisture absorbing calcium chloride crystals
 

Julian wrote:

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

If you leave it long enough you will get just liquid, the situation that you
describe is because the liquid is saturated.

So, the crystals started absorbing moisuture, to the point of being
dissolved in the moisture they were absorbing.

As this happens, the stuff heats up (apparently this reaction produces a
lot of heat) and the water becomes super-saturated, and continues to
dissolve more of the crystals.

Then it starts cooling down, and as it cools down some of the calcium
chloride precipitates out of the water.

Is that correct?

Daniele

Moisture absorbing calcium chloride crystals
 

D.M. Procida wrote:
I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Are there like to be any nasty substances released into the air as it
dries?

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

I suspect it's not pure CaCl.

Anyway.
Mere radiator won't cut it.
Take it all out, and place in a flat baking tray or something, and place
covered in an oven at 150C till dry.
Then break up and put the

Moisture absorbing calcium chloride crystals
 

D.M. Procida wrote:

I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Are there like to be any nasty substances released into the air as it
dries?

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

Thanks,

Daniele

These things are truly crap. If you redry them in the house all the
water vapour absorbed is dumped back into the air again.

If you keep using it, buying bagged lime from B&Q may prove cheaper.
But just as poor a performer. Fwiw quicklime would be more effective,
though less safe.


NT

Moisture absorbing calcium chloride crystals
 

"D.M. Procida" wrote in
message
...
Julian wrote:

Why am I left with a solid and a liquid, not just some dissolved
calcium
chloride?

If you leave it long enough you will get just liquid, the situation that
you
describe is because the liquid is saturated.

So, the crystals started absorbing moisuture, to the point of being
dissolved in the moisture they were absorbing.

As this happens, the stuff heats up (apparently this reaction produces a
lot of heat) and the water becomes super-saturated, and continues to
dissolve more of the crystals.

Then it starts cooling down, and as it cools down some of the calcium
chloride precipitates out of the water.

Is that correct?

Not really - far too complicated! The crystals absorb moisture until they
start to dissolve, the liquid thus produced is also hydroscopic and
continues to absorb water until the crystals have all dissolved. After that
the liquid still absorbs further moisture, but with reducing affectivity as
the concentration of calcium chloride reduces.

I was once given one of those 'throwaway' dehumidifier containers once. It
had a mark on the side about 1/2 way up, when the level reached the mark it
was time for a new one.

Julian.

Moisture absorbing calcium chloride crystals
 

Julian wrote:

Not really - far too complicated! The crystals absorb moisture until they
start to dissolve, the liquid thus produced is also hydroscopic and
continues to absorb water until the crystals have all dissolved. After that
the liquid still absorbs further moisture, but with reducing affectivity as
the concentration of calcium chloride reduces.

So I could leave it longer to absorb moisture, until all the solid has
disappeared? Would I be better off pouring the liquid or not?

Daniele

Moisture absorbing calcium chloride crystals
 

D.M. Procida wrote:

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

No, the solid mass is a mixture of calcium sulphate and calcium
carbonate -- basically trash impurities, because the "calcium chloride"
sold for these things is far from pure.

If you were to heat the calcium chloride solution and evaporate it, you
could recover the calcium chloride and re-use that. OTOH you'd probably
have to pay the energy costs of doing so. If you had a big damp problem
and a source of waste heat, then it _might_ start to make sense.

Moisture absorbing calcium chloride crystals
 

D.M. Procida wrote:
Julian wrote:

Not really - far too complicated! The crystals absorb moisture until they
start to dissolve, the liquid thus produced is also hydroscopic and
continues to absorb water until the crystals have all dissolved. After that
the liquid still absorbs further moisture, but with reducing affectivity as
the concentration of calcium chloride reduces.

So I could leave it longer to absorb moisture, until all the solid has
disappeared? Would I be better off pouring the liquid or not?

Leave it.
What may make more difference is to take some packing tape, and go over
the door edge insides, so that you have half on the door, half off the door.
Then fold over the exposed edge of tape, so you have a draughtproofing
seal.
This may give some hope of the dehumidifier thing working, though it'd
really need a vapour barrier to do any good at all.

Does it actually reduce dampness at all?

Moisture absorbing calcium chloride crystals
 

Ian Stirling wrote:

Does it actually reduce dampness at all?

from what I've seen of thesse things, they do absorb water vapour, but
the amount of absorption is only a small proportion of the damp
present, so they have approximately no effect on the situation. Theyre
basically junk products.


NT

Moisture absorbing calcium chloride crystals
 

I bought an electric dehumidifier from ALDI a month or so ago for under
£20. It collects about 150ml of water from our front room in a 7 hour
period (over night). It seems to have no effect on condensation levels
on our single glazed bay window, which was the purpose of the purchase.

Philip

Moisture absorbing calcium chloride crystals
 

wrote:
Ian Stirling wrote:

Does it actually reduce dampness at all?

from what I've seen of thesse things, they do absorb water vapour, but
the amount of absorption is only a small proportion of the damp
present, so they have approximately no effect on the situation. Theyre
basically junk products.


I have several dishes of calcium choride under the floor in my
narrowboat. it does keep it dry down there. But that it an
environment where new water vapour enters only slowly so only a small
amount of dehydration is needed.

As others have pointed out, calcium chloride is deliquessant, not
merely hygroscopic; it absorbs so much water that it completely
dissolves in it.

Robert

Moisture absorbing calcium chloride crystals
 

"Robert Laws" wrote in message
ups.com...


I have several dishes of calcium choride under the floor in my
narrowboat. it does keep it dry down there. But that it an
environment where new water vapour enters only slowly so only a small
amount of dehydration is needed.

I use it (in tubs) in the boiler of my steam roller. (over winter) It keeps
the RH close to zero and effectively stops the steel boiler rusting
internally. The crystals last almost 6 months because the boiler is just
about air tight, give or take some small leakage from gland packings etc.

Julian.

Moisture absorbing calcium chloride crystals
 

Moisture absorbing calcium chloride crystals
 

wrote:

I bought an electric dehumidifier from ALDI a month or so ago for under
£20.

what kind of dh can you get for £20? CaCl plus fan?

Peltier? The heat from the hot side conducts back across when the
power cycles off and de-frosts it. Woefully inefficient on power, but
a neat little minimal design.

Moisture absorbing calcium chloride crystals
 

Andy Dingley wrote:
wrote:

I bought an electric dehumidifier from ALDI a month or so ago for under
£20.

what kind of dh can you get for £20? CaCl plus fan?

Peltier? The heat from the hot side conducts back across when the
power cycles off and de-frosts it. Woefully inefficient on power, but
a neat little minimal design.

interesting idea, ta.

NT

Moisture absorbing calcium chloride crystals
 

In article
, D.M.
Procida wrote:
I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
Calcium chloride is a pretty dodgy chemical to have around the
house. I'd expect it to find buckets of it in my father's house
(ex-industrial chemist, with a wife who's learned over 50 years to put
containers of chemicals back in the cupboard without opening them.
Are you really really certain that this device recommends use of
granular calcium chloride?

cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

See later for the likely chemistry.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Two tenths of bugger all.

Are there like to be any nasty substances released into the air as it
dries?

No.

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

Calcium chloride will absorb copious water from the atmosphere. The
resulting nearly neutral solution of CaCl2 will pick up small amounts of
CO2 from the atmosphere, which will produce a precipitate of calcium
carbonate. That'll be your solid residue.
Calcium carbonate itself is not harmful, but with the chloride
you'll have a mix that'll dehydrate your skin pretty damned quick. And if
you get it into a cut, you'll really know about it. Get it in your eye (or
the inquisitive brat's eye) and you'll have fun trying to get your eye
under the shower while screaming in pain. It'd not be easy to blind
yourself, but by no means impossible.
Refer to previous description of the ex-industrial chemist : Dad
and I wouldn't be bothered about such stuff round the house, but we'd keep
it under lock and key.

Your mileage may vary, but I wouldn't use CaCl2 as a domestic
dehydrating material. I doubt Dad would either.

--
Aidan
Aberdeen, Scotland
Written at Fri, 08 Dec 2006 00:22 GMT, but posted later.

Moisture absorbing calcium chloride crystals
 

In article , Julian wrote:
the liquid thus produced is also hydroscopic

"hygroscopic"
(pet peeve)

--
Aidan
Aberdeen, Scotland
Written at Fri, 08 Dec 2006 00:36 GMT, but posted later.

Moisture absorbing calcium chloride crystals
 

Aidan Karley lid wrote:
In article , Julian wrote:
the liquid thus produced is also hydroscopic

"hygroscopic"
Hyperscopic.

Moisture absorbing calcium chloride crystals
 

Aidan Karley lid wrote:
In article
, D.M.
Procida wrote:
I have a little plastic thing from Woolworths into which I pour calcium
chloride crystals, to act as a moisture absorber in an under-stairs
Calcium chloride is a pretty dodgy chemical to have around the
house. I'd expect it to find buckets of it in my father's house
(ex-industrial chemist, with a wife who's learned over 50 years to put
containers of chemicals back in the cupboard without opening them.
Are you really really certain that this device recommends use of
granular calcium chloride?

cupboard which is damper than it ought to be.

What I'm left with after some time is a liquid and a solid mass.

See later for the likely chemistry.

If I pour off the liquid, and leave the solid mass in a warm dry place,
say on top of a radiator, will it be any good at absorbing moisture from
the air once again?

Two tenths of bugger all.

Are there like to be any nasty substances released into the air as it
dries?

No.

Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

Calcium chloride will absorb copious water from the atmosphere. The
resulting nearly neutral solution of CaCl2 will pick up small amounts of
CO2 from the atmosphere, which will produce a precipitate of calcium
carbonate. That'll be your solid residue.

If this was true, the calcium has to go out of solution too, as half of
the CaCO2.
For each molecule of CaCO2 that's produced, you've got to have an atom
of Chlorine that's released into the air (after the solution is
saturated by chlorine)

Moisture absorbing calcium chloride crystals
 

Ian Stirling wrote:

Aidan Karley lid wrote:
In article
, D.M.
Procida wrote:
Why am I left with a solid and a liquid, not just some dissolved calcium
chloride?

Calcium chloride will absorb copious water from the atmosphere. The
resulting nearly neutral solution of CaCl2 will pick up small amounts of
CO2 from the atmosphere, which will produce a precipitate of calcium
carbonate. That'll be your solid residue.

If this was true, the calcium has to go out of solution too, as half of
the CaCO2.
For each molecule of CaCO2 that's produced, you've got to have an atom
of Chlorine that's released into the air (after the solution is
saturated by chlorine)

Ian,

you need to brush up a little on your chemistry, I'm afraid.

1) Calcium Carbonate is CaCO3
2) CaCO3 is ionic, so talking about 'molecules' of CaCO3 is not correct
3) Chlorine gas is molecular - Cl2. It won't be monatomic in air in
normal conditions
4) The reaction equation implied by your statements is not CaCl2 + CO2
= CaCO2 + Cl2

Calcium Chloride is hygroscopic, such that it will absorb water from
normal atmospheres to the extent of dissolving itself - and the the
solution produced continues to absorb water. In solution it will be
ionic. Ths is actually an equilibrium process - at some point the
solution will be dilute enough to not absorb any more water from the
atmosphere.

Carbon Dioxide also dissolves in water producing 'carbonic acid' -
another equilibrium process whereby there will also be carbonate and
hygrogen carbonate ions in solution. There is also another equilibrium
process between solid calcium carbonate and calcium carbonate in
solution (as a mixture of the carbonate and hydrogen carbonate).

One thing is certain, though - chlorine gas is not evolved by the
solution.

To a certain extent, all chemical reactions can be regarded as
equilibrium reactions. However, with most of them, the equilibrium lies
so far over to one side (so to speak) that it is a useful shorthand to
say that reactants are transformed into products.

Sid

Moisture absorbing calcium chloride crystals
 

replying to Philipj.cosson, Stu wrote:
I have the same problem, got myself a karcher window vacuum, takes moisture
away quickly

--
for full context, visit https://www.homeownershub.com/uk-diy...ls-344372-.htm

Moisture absorbing calcium chloride crystals
 

Please if you must use this broken interface to Usenet, Look at the date of
the post you are replying to before you put electrons to internet so to
speak. The Home owners club interface seems to ignore years so you can very
easily find a post from many years ago coming back around on there. I just
looked at the origin of this one on that site and found the following date.

posted on December 6, 2006, 11:27 am

Which makes a reply look a little strange!
Brian
--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Stu" m wrote in message
...
replying to Philipj.cosson, Stu wrote:
I have the same problem, got myself a karcher window vacuum, takes
moisture
away quickly
--
for full context, visit
https://www.homeownershub.com/uk-diy...ls-344372-.htm

Moisture absorbing calcium chloride crystals
 

On Sat, 13 Jan 2018 08:44:17 -0000
"Brian Gaff" wrote:

You think these hit-and-run "contributors" ever look at that thread
again?

Please if you must use this broken interface to Usenet, Look at the
date of the post you are replying to before you put electrons to
internet so to speak. The Home owners club interface seems to ignore
years so you can very easily find a post from many years ago coming
back around on there. I just looked at the origin of this one on that
site and found the following date.

posted on December 6, 2006, 11:27 am

Which makes a reply look a little strange!
Brian

Moisture absorbing calcium chloride crystals
 

I'd say quite often yes, as I'm sure this particular person has been on
before. The message was really to serve as a warning to others though. I've
seen the sarcastic posts so I thought I'd try a different tack. Its hard to
block them on my client, as I do not have the ability to filter on the
correct strings.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Rob Morley" wrote in message
news:20180113140603.208a2ad8@Mars...
On Sat, 13 Jan 2018 08:44:17 -0000
"Brian Gaff" wrote:

You think these hit-and-run "contributors" ever look at that thread
again?

Please if you must use this broken interface to Usenet, Look at the
date of the post you are replying to before you put electrons to
internet so to speak. The Home owners club interface seems to ignore
years so you can very easily find a post from many years ago coming
back around on there. I just looked at the origin of this one on that
site and found the following date.

posted on December 6, 2006, 11:27 am

Which makes a reply look a little strange!
Brian